While a number of transcription factors involved in floral development have been identified, the exact mechanisms by which many of these transcription factors function are unknown. The experiments in this proposal aim to elucidate the molecular mechanisms by which two flower specific transcription factors function to regulate transcription during flower development. One of these transcription factors, encoded by the APETALA3 (APS) gene is a floral organ identity gene important for both petal and stamen development, and the other, SUPERMAN (SUP), is important for boundary formation between two specific floral domains, or whorls. The objective of the proposed experiments is to elucidate how APS and SUP function at the molecular level to mediate transcriptional activation and repression of target genes, respectively. Specifically, results will indicate whether APS- and SUP-mediated transcriptional regulation involves chromatin- and/or epigenetic-level changes, as well as elucidate APS and SUP co-factors involved in the process of transcriptional regulation.